Association of Serum Adropin Concentrations with Diabetic Nephropathy

Serum Adropin Levels and Body Mass Composition in Kidney Transplant Recipients-Are There Sex Differences?

Adropin is a secretory peptide that regulates glucose, lipid, and protein metabolism, which is closely related to obesity, insulin resistance, dyslipidemia, and atherogenesis. The serum adropin level is related to sex and depends upon nutritional preferences. This study aims to determine the association between serum adropin levels and body composition parameters in kidney transplant recipients (KTRs), especially emphasizing sex differences. Our case-control study involved 59 KTRs (28 postmenopausal women and 31 men) who were divided into two groups according to sex, and each group of those KTRs was further divided into higher or lower adropin values than the mean value in each sex group. Univariate regression showed a negative association of adropin levels with most anthropometric and body composition parameters in men's KTRs. Contrary to this, the serum adropin level was negatively associated only with phase angle in postmenopausal female KTRs. Multivariate regression showed that skeletal muscle mass and phase angle were the only negative predictors in women's KTRs, whereas in men, negative predictors were BMI and body water. These findings imply that adropin could have a different impact on metabolic homeostasis in KTRs regarding sex and could be considered a negative predictor of body composition in KTRs.

Adropin - A new player in energy regulation predicts long-term prognosis of patients with acute myocardial infarction

Background

As a novel energy homeostasis regulator, Adropin not only plays a vital part in meditating energy metabolism, but also has a certain correlation with atherosclerotic diseases. The purpose of this study was to evaluate the effect of Adropin on the long-term prognosis of patients with acute myocardial infarction (AMI).

Methods

162 recruited patients with AMI were divided into low Adropin group (Adropin<166.3 pg/mL, n = 82) and high Adropin group (Adropin≥166.3 pg/mL, n = 80), according to the mean value of serum Adropin level. Patients were followed up and major adverse cardiac events (MACEs) were recorded. The Kaplan-Meier method and Cox regression model were used to evaluate the survival of patients and the related factors of cardiac events.

Results

Diabetes was more common in low Adropin group than that in high Adropin group (P < 0.05). Patients were followed up for an average of 50.3 ± 19.2 months. MACEs occurred in 37 patients (22.8%), including 6 cardiac deaths (3.7%), 14 recurrent myocardial infarction (8.6%) and 17 rehospitalization of heart failure (10.5%). The incidence of recurrent myocardial infarction in low Adropin group was higher than that in high Adropin group (13.4% vs 3.8%, P < 0.05). There was no significant difference in the overall incidence of MACE, cardiac death and rehospitalization of heart failure between the two groups. Kaplan-Meier method (log rank test) analysis results showed that patients with low Adropin had lower survival rate without recurrent myocardial infarction (log rank P = 0.035).

Conclusion

Low Adropin level was associated with an increased risk of long-term recurrent myocardial infarction in patients with AMI.

Serum Levels of Adropin Improve the Predictability of MELD and Child-Pugh Score in Cirrhosis: Results of Proof-of-Concept Clinical Trial

Adropin is a peptide that was suggested to have a role in cirrhosis. The present study aimed to determine the ability to use serum adropin levels to improve their prediction accuracy as an adjunct to the current scores. In a single-center, proof-of-concept study, serum adropin levels were determined in thirty-three cirrhotic patients. The data were analyzed in correlation with Child-Pugh and MELD-Na scores, laboratory parameters, and mortality. Adropin levels were higher among cirrhotic patients that died within 180 days (1,325.7 ng/dL vs. 870.3 ng/dL, p = 0.024) and inversely correlated to the time until death (r ² = 0.74). The correlation of adropin serum levels with mortality was better than MELD or Child-Pough scores (r ² = 0.32 and 0.38, respectively). Higher adropin levels correlated with creatinine (r ² = 0.79. p < 0.01). Patients with diabetes mellitus and cardiovascular diseases had elevated adropin levels. Integrating adropin levels with the Child-Pugh and MELD scores improved their correlation with the time of death (correlation coefficient: 0.91 vs. 0.38 and 0.67 vs. 0.32). The data of this feasibility study suggest that combining serum adropin with the Child-Pugh score and MELD-Na score improves the prediction of mortality in cirrhosis and can serve as a measure for assessing kidney dysfunction in these patients.

Circulating levels of adropin and diabetes: a systematic review and meta-analysis of observational studies

OBJECTIVE

Adropin, a newly identified regulatory protein has garnered attention given its potential role in metabolism regulation, especially glucose metabolism and insulin resistance. However, studies on the association between adropin and type 2 diabetes mellitus (T2DM) are equivocal. The aim of this study is to assess the association between serum adropin levels and T2DM using a systematic review and meta-analysis of observational studies.

METHODS

PubMed, Scopus, ISI Web of science, and Google Scholar were searched, up to August 2022, for studies that reported the association between serum levels of adropin in adults with T2DM compared to a control group without diabetes. A random-effect model was used to compute the pooled weighted mean difference (WMD) with 95% confidence intervals (CI).

RESULTS

Meta-analysis of 15 studies (n = 2813 participants) revealed that the serum adropin concentrations were significantly lower in patients with T2DM compared with the control group (WMD= -0.60 ng/mL, 95% CI: -0.70 to -0.49; I² = 99.5%). Subgroup analysis also found lower concentration of adropin in patients with T2DM who were otherwise healthy compared to a control group (n = 9; WMD=-0.04 ng/ml, 95% CI= -0.06 to -0.01, p = 0.002; I² = 96.4).

CONCLUSIONS

Our study showed adropin levels are lower in patients with diabetes compared to a control group without diabetes. However, the limitations of observational studies challenge the validity of the results, and further investigations are needed to confirm the veracity of these findings and additionally explore possible mechanisms.

Adropin Predicts Chronic Kidney Disease in Type 2 Diabetes Mellitus Patients with Chronic Heart Failure

Adropin is a multifunctional secreted protein, which is involved in the metabolic modulation of the heart-brain-kidney axis in heart failure (HF). The aim of the study was to detect the plausible predictive value of serum levels of adropin for chronic kidney disease (CKD) grades 1-3 in type 2 diabetes mellitus (T2DM) patients with chronic HF. We enrolled 417 T2DM individuals with chronic HF and subdivided them into two groups depending on the presence of CKD. The control group was composed of 25 healthy individuals and 30 T2DM patients without HF and CKD. All eligible patients underwent an ultrasound examination. Adropin was detected by ELISA in blood samples at the study baseline. We found that adropin levels in T2DM patients without HF and CKD were significantly lower than in healthy volunteers, but they were higher than in T2DM patients with known HF. The optimal cut-off point for adropin levels was 2.3 ng/mL (area under the curve [AUC] = 0.86; 95% CI = 0.78-0.95; sensitivity = 81.3%, specificity = 77.4%). The multivariate logistic regression adjusted for albuminuria/proteinuria showed that serum levels of adropin <2.30 ng/mL (OR = 1.55; p = 0.001) independently predicted CKD. Conclusions: Low levels of adropin in T2DM patients with chronic CH seem to be an independent predictor of CKD at stages 1-3.

Role of adropin in arterial stiffening associated with obesity and type 2 diabetes

Adropin is a peptide largely secreted by the liver and known to regulate energy homeostasis; however, it also exerts cardiovascular effects. Herein, we tested the hypothesis that low circulating levels of adropin in obesity and type 2 diabetes (T2D) contribute to arterial stiffening. In support of this hypothesis, we report that obesity and T2D are associated with reduced levels of adropin (in liver and plasma) and increased arterial stiffness in mice and humans. Establishing causation, we show that mesenteric arteries from adropin knockout mice are also stiffer, relative to arteries from wild-type counterparts, thus recapitulating the stiffening phenotype observed in T2D db/db mice. Given the above, we performed a set of follow-up experiments, in which we found that 1) exposure of endothelial cells or isolated mesenteric arteries from db/db mice to adropin reduces filamentous actin (F-actin) stress fibers and stiffness, 2) adropin-induced reduction of F-actin and stiffness in endothelial cells and db/db mesenteric arteries is abrogated by inhibition of nitric oxide (NO) synthase, and 3) stimulation of smooth muscle cells or db/db mesenteric arteries with a NO mimetic reduces stiffness. Lastly, we demonstrated that in vivo treatment of db/db mice with adropin for 4 wk reduces stiffness in mesenteric arteries. Collectively, these findings indicate that adropin can regulate arterial stiffness, likely via endothelium-derived NO, and thus support the notion that "hypoadropinemia" should be considered as a putative target for the prevention and treatment of arterial stiffening in obesity and T2D.NEW & NOTEWORTHY Arterial stiffening, a characteristic feature of obesity and type 2 diabetes (T2D), contributes to the development and progression of cardiovascular diseases. Herein we establish that adropin is decreased in obese and T2D models and furthermore provide evidence that reduced adropin may directly contribute to arterial stiffening. Collectively, findings from this work support the notion that "hypoadropinemia" should be considered as a putative target for the prevention and treatment of arterial stiffening in obesity and T2D.

Crosstalk between the liver and kidney in diabetic nephropathy

Diabetic nephropathy (DN) is a serious complication of diabetes, and its pathogenesis has not been fully elucidated. Recently, communication between organs has gradually become a new focus in the study of diseases pathogenesis, and abnormal interorgan communication has been proven to be involved in the occurrence and progression of many diseases. As an important metabolic organ in the human body, the liver plays an important role in maintaining homeostasis in humans. The liver secretes a series of proteins called hepatokines that affect adjacent and distal organs through paracrine or endocrine signaling pathways. In this review, we summarize some of the hepatokines identified to date and describe their roles in DN to discuss the possibility that the liver-renal axis is potentially useful as a therapeutic target for DN. We summarize the important hepatokines identified thus far and discuss their relationship with DN. We propose for the first time that the "liver-renal axis" is a potential therapeutic target in individuals with DN.

Adropin’s Role in Energy Homeostasis and Metabolic Disorders

Adropin is a novel 76-amino acid-peptide that is expressed in different tissues and cells including the liver, pancreas, heart and vascular tissues, kidney, milk, serum, plasma and many parts of the brain. Adropin, encoded by the Enho gene, plays a crucial role in energy homeostasis. The literature review indicates that adropin alleviates the degree of insulin resistance by reducing endogenous hepatic glucose production. Adropin improves glucose metabolism by enhancing glucose utilization in mice, including the sensitization of insulin signaling pathways such as Akt phosphorylation and the activation of the glucose transporter 4 receptor. Several studies have also demonstrated that adropin improves cardiac function, cardiac efficiency and coronary blood flow in mice. Adropin can also reduce the levels of serum triglycerides, total cholesterol and low-density lipoprotein cholesterol. In contrast, it increases the level of high-density lipoprotein cholesterol, often referred to as the beneficial cholesterol. Adropin inhibits inflammation by reducing the tissue level of pro-inflammatory cytokines such as tumor necrosis factor alpha and interleukin-6. The protective effect of adropin on the vascular endothelium is through an increase in the expression of endothelial nitric oxide synthase. This article provides an overview of the existing literature about the role of adropin in different pathological conditions.

The Clinical Value of Serum Adropin Level in Early Detection of Diabetic Nephropathy

BACKGROUND/AIMS

Adropin is a metabolic hormone secreted by the liver, brain, and many peripheral tissues and is involved in energy homeostasis and insulin sensitivity. Some reports have indicated a significant decrease in serum adropin levels in type 2 diabetic patients. However, the significance of a decline in adropin level in early detection of diabetic nephropathy (DN) remains to be clarified. The purpose of this study was to evaluate the serum levels of adropin in patients with type 2 diabetes with and without nephropathy.

METHODS

A total of 135 unrelated subjects (including 45 diabetic patients with nephropathy, 45 without nephropathy, and 45 healthy controls) were enrolled in this study. Fasting venous blood samples were collected from all patients. Serum adropin levels of all cases were analyzed by an enzyme-linked immunosorbent assay method. The correlations of serum adropin levels with anthropometric and biochemistry variables were determined. Logistic regression was performed to assess the association of adropin with odds of nephropathy. A receiver operating characteristic (ROC) curve was obtained to explore the optimum serum adropin concentration in distinguishing diabetic patients with and without nephropathy.

RESULTS

Diabetic patients with nephropathy showed lower serum adropin levels than those in patients without nephropathy and healthy controls (p < 0.001). Pearson correlation analysis indicated that serum adropin was negatively correlated with BMI, FBS, HbA1c, blood urea, creatinine, LDL, and ACR and positively correlated with HDL and albumin. Logistic regression analysis showed that serum adropin was correlated with decreased risk of developing diabetic nephropathy. Moreover, in ROC analysis, at cutoff value 3.20 (mg/dL) with an AUC = 0.830, adropin had 80% sensitivity and 60% specificity for distinguishing the diabetic nephropathy.

CONCLUSIONS

This study demonstrates that decreased level of adropin is associated with renal dysfunction in patients with type 2 diabetes mellitus. Serum adropin concentrations may be used as a biomarker for early detection of diabetic nephropathy.

Inflammatory response and matrix metalloproteinases in chronic kidney failure: Modulation by adropin and spexin

Chronic kidney disease is a major global public health problem. The peptide hormones adropin and spexin modulate many physiological functions such as energy balance and glucose, lipid and protein metabolism. However, it is unclear whether these peptides may exert effects on renal damage, tissue remodeling, and inflammatory conditions. In view of the limited information, we aimed to investigate the effect of adropin and spexin on matrix metalloproteinase and inflammatory response genes a rat model of adenine-induced chronic kidney failure. Chronic kidney failure was induced in rats by administering adenine hemisulfate. Renal function was determined in an autoanalyzer. Histopathological modifications were assessed by H&E staining. mRNA expression levels of ALOX 15, COX 1, COX 2, IL-1β, IL-10, IL-17A, IL-18 IL-21, IL-33, KIM-1, MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, MMP-13, NGAL, TGFβ1, TIMP-1, and TNFα in kidney tissue were measured by qPCR. Our results showed an increase of 24-h urine volume, serum creatinine, BUN, and urine protein levels in group with adenine-induced CKF. Adropin and spexin treatments decreased urine protein and 24-h urine volume. Renal damage, TIMP-1, IL-33, and MMP-2 increased after CKF induction, while COX 1, MMP-9, and MMP-13 levels were significantly reduced. Furthermore, KIM-1, TIMP-1, IL-33, and MMP-2 were downregulated by spexin treatment. Renal damage, NGAL, TIMP-1 IL-17A, IL-33, MMP-2, and MMP-3 decreased after adropin treatment, while MMP-13 levels were upregulated. Treatment with adropin+spexin decreased KIM-1, NGAL, TIMP-1, IL-1β, IL-17A, IL-18, IL-33, ALOX 15, COX 1, COX 2, TGFβ1, TNFα, MMP-2, MMP-3, and MMP-7, but increased MMP-13 levels. Our findings revealed that inflammatory response and MMP genes were modulated by adropin and spexin. These peptides may have protective effects on inflammation and chronic kidney damage progression.

New Peptides as Potential Players in the Crosstalk Between the Brain and Obesity, Metabolic and Cardiovascular Diseases

According to the World Health Organization report published in 2016, 650 million people worldwide suffer from obesity, almost three times more than in 1975. Obesity is defined as excessive fat accumulation which may impair health with non-communicable diseases such as diabetes, cardiovascular diseases (hypertension, coronary artery disease, stroke), and some cancers. Despite medical advances, cardiovascular complications are still the leading causes of death arising from obesity. Excessive fat accumulation is caused by the imbalance between energy intake and expenditure. The pathogenesis of this process is complex and not fully understood, but current research is focused on the role of the complex crosstalk between the central nervous system (CNS), neuroendocrine and immune system including the autonomic nervous system, adipose tissue, digestive and cardiovascular systems. Additionally, special attention has been paid to newly discovered substances: neuropeptide 26RFa, preptin, and adropin. It was shown that the above peptides are synthesized both in numerous structures of the CNS and in many peripheral organs and tissues, such as the heart, adipose tissue, and the gastrointestinal tract. Recently, particular attention has been paid to the role of the presented peptides in the pathogenesis of obesity, metabolic and cardiovascular system diseases. This review summarizes the role of newly investigated peptides in the crosstalk between brain and peripheral organs in the pathogenesis of obesity, metabolic, and cardiovascular diseases.

Optimal therapeutic adropin dose intervention in mice and rat animal models: A systematic review

Background and Aim:

Adropin is a hormone encoded by the Enho gene, which is associated with energy homeostasis. Preclinical studies using animal models have shown that adropin plays a role in enhancing glucose homeostasis and dyslipidemia. Lately, several studies on animal models have been performed to examine the therapeutic and pathophysiological effects of adropin in many disorders. The aim of this systematic review was to identify the ideal adropin dose in mice and rat animal models.

Materials and Methods:

We systematically searched PubMed, Science Direct, and Scopus databases from 2008 to 2020. The terms used in the search were “adropin,” “adropin doses in animal models,” “glucose homeostasis related to adropin,” and “adropin therapeutic effects on rats and mice.” Articles that included non-adropin doses, in vitro studies, and factors affecting adropin levels were excluded from the study.

Results:

Of the total 179 qualified studies, six studies were included. We found that a daily injection of 450 nmol/kg of adropin for 3 days might be considered the optimum dose of effect in mice, whereas injection of 2.1 mg/kg once a day for 10 successive days might be the optimal effective dose in rats.

Conclusion:

Additional investigations are needed to determine the optimum dose of adropin to be used as a therapeutic intervention depending on the animal model.

Correlation of Serum Adropin Levels with Risk Factors of Cardiovascular Disease in Hemodialysis Patients

Background: Many preclinical studies have shown that adropin has physiological effects such as regulating glucose, lipid, and energy metabolism, protecting endothelial cells and antiatherosclerosis. Our aim is to explore whether adropin is correlated with risk factors of cardiovascular disease (CVD) in hemodialysis (HD) patients. Methods: We recruited 170 HD patients and 120 healthy controls. The serum adropin concentration and clinical characteristics were measured. Results: The serum adropin concentration in HD patients was significantly lower than that in healthy controls and which in HD patients with CVD or diabetes mellitus (DM) was significantly lower than that in patients without CVD or DM. The correlation analysis showed that serum adropin levels were correlated negatively with Age, CVD history, DM history, C-reactive protein, type B natriuretic peptide, phosphorus, intact parathyroid hormone, carotid artery plaque amount and carotid intima-media thickness (CIMT), left ventricular septal thickness (LVSTd), and left ventricular posterior wall thickness, whereas it was correlated positively with albumin, hemoglobin, serum creatinine and Kt/V, and ejection fraction value. Partial correlation analysis verified that serum adropin levels were correlated negatively with CIMT, and multiple linear regression analysis revealed that low serum adropin levels may be one independent predictors of CIMT. However, the partial correlation analysis and multiple linear regression analysis did not identify the significant correlation between serum adropin levels and LVSTd. Conclusions: Our study revealed that serum adropin level is significantly correlated with risk factors of CVD and low serum adropin levels may be a potential predictor of CVD in HD patients.

Serum Adropin Levels in Patients on Hemodialysis

Adropin is a novel pleotropic peptide involved in energy homeostasis, with possible contribution to cardiovascular protection through production of nitric oxide and subsequent blood pressure regulation. Given that patients undergoing hemodialysis (HD) are related with high cardiovascular risk, hyperlipidemia, chronic low-grade inflammation, and malnutrition the aim of our study was to investigate serum adropin levels in HD patients to evaluate possible associations with nutritional status and other relevant clinical and laboratory parameters. The study included 70 patients on HD and 60 healthy controls. Serum adropin levels were determined by an enzyme-linked immunosorbent assay in a commercially available diagnostic kit. Serum adropin levels were significantly lower in the HD group compared to the control group (2.20 ± 0.72 vs. 4.05 ± 0.93 ng/mL, p < 0.001). Moreover, there was a significant negative correlation with malnutrition-inflammation score (r = −0.476, p < 0.001), dialysis malnutrition score (r = −0.350, p = 0.003), HD duration (r = −0.305, p = 0.010), and high sensitivity C-reactive protein (hsCRP) (r = −0.646, p < 0.001). Additionally, there was a significant negative correlation between adropin levels and pre-dialysis systolic (r = −0.301, p = 0.011) and diastolic blood pressure (r = −0.299, p = 0.011). These results are implying that adropin is potentially involved in the pathophysiological mechanisms of chronic kidney disease (CKD)/HD and its complications. However, future larger scale longitudinal studies need to further address it.

Adropin as a potential mediator of the metabolic system-autonomic nervous system-chronobiology axis: Implementing a personalized signature-based platform for chronotherapy

Adropin is a peptide hormone, which plays a role in energy homeostasis and controls glucose and fatty acid metabolism. Its levels correlate with changes in carbohydrate-lipid metabolism, metabolic diseases, central nervous system function, endothelial function and cardiovascular disease. Both metabolic pathways and adropin are regulated by the circadian clocks. Here, we review the roles of the autonomic nervous system and circadian rhythms in regulating metabolic pathways and energy homeostasis. The beneficial effects of chronotherapy in various systems are discussed. We suggest a potential role for adropin as a mediator of the metabolic system-autonomic nervous system axis. We discuss the possibility of establishing an individualized adropin and circadian rhythm-based platform for implementing chronotherapy, and variability signatures for improving the efficacy of adropin-based therapies are discussed.

The Usefulness of Diagnostic Panels Based on Circulating Adipocytokines/Regulatory Peptides, Renal Function Tests, Insulin Resistance Indicators and Lipid-Carbohydrate Metabolism Parameters in Diagnosis and Prognosis of Type 2 Diabetes Mellitus with Obesity

The quantitative analysis of selected regulatory molecules, i.e., adropin, irisin, and vaspin in the plasma of obese patients with newly diagnosed, untreated type 2 diabetes mellitus, and in the same patients after six months of using metformin, in relation to adropinemia, irisinemia and vaspinemia in obese individuals, was performed. The relationship between plasma concentration of the adipocytokines/regulatory peptides and parameters of renal function (albumin/creatinine ratio-ACR, estimated glomerular filtration rate-eGFR), values of insulin resistance indicators (Homeostatic Model Assessment of Insulin Resistance (HOMA-IR2), Homeostatic Model Assessment of Insulin Sensitivity (HOMA-S), Homeostatic Model Assessment of β-cell function (HOMA-B), quantitative insulin sensitivity check index (QUICKI), insulin), and parameters of carbohydrate-lipid metabolism (fasting plasma glucose-FPG, glycated hemoglobin-HbA_1C, estimated glucose disposal rate-eGDR, fasting lipid profile, TG/HDL ratio) in obese type 2 diabetic patients was also investigated. Circulating irisin and vaspin were found significantly different in subjects with metabolically healthy obesity and in type 2 diabetic patients. Significant increases in blood levels of both analyzed adipokines/regulatory peptides were observed in diabetic patients after six months of metformin treatment, as compared to pre-treatment levels. The change in plasma vaspin level in response to metformin therapy was parallel with the improving of insulin resistance/sensitivity parameters. An attempt was made to identify a set of biochemical tests that would vary greatly in obese non-diabetic subjects and obese patients with type 2 diabetes, as well as a set of parameters that are changing in patients with type 2 diabetes under the influence of six months metformin therapy, and thus differentiating patients' metabolic state before and after treatment. For these data analyses, both statistical measures of strength of the relationships of individual parameters, as well as multidimensional methods, including discriminant analysis and multifactorial analysis derived from machine learning methods, were used. Adropin, irisin, and vaspin were found as promising regulatory molecules, which may turn out to be useful indicators in the early detection of T2DM and differentiating the obesity phenotype with normal metabolic profile from T2DM obese patients. Multifactorial discriminant analysis revealed that irisin and vaspin plasma levels contribute clinically relevant information concerning the effectiveness of metformin treatment in T2D patients. Among the sets of variables differentiating with the highest accuracy the metabolic state of patients before and after six-month metformin treatment, were: (1) vaspin, HbA1c, HDL, LDL, TG, insulin, and HOMA-B (ACC = 88 [%]); (2) vaspin, irisin, QUICKI, and eGDR (ACC = 86 [%]); as well as, (3) vaspin, irisin, LDL, HOMA-S, ACR, and eGFR (ACC = 86 [%]).

A Review of Adropin as the Medium of Dialogue between Energy Regulation and Immune Regulation

Adropin is a secretory protein encoded by the energy balance gene and is closely associated with regulation of energy metabolism and insulin resistance. The clinical findings demonstrated its decreased expression in various inflammatory diseases, its negative correlation with the expression levels of inflammatory cytokines, and its potential anti-inflammatory effects. We speculate that adropin plays a pivotal regulatory role in immune cells and inflammatory factors. In this study, we reviewed the advances in researches concentrated on immunological effects of adropin.

Serum Adropin Levels Are Reduced in Adult Patients with Nonalcoholic Fatty Liver Disease

OBJECTIVES

Adropin is a novel marker of metabolic syndrome and insulin resistance. The aim of this study was to explore the association of serum adropin levels with hepatosteatosis among adult patients.

MATERIALS AND METHODS

Serum biochemical parameters including liver and renal function tests, insulin levels, and serum adropin levels were compared between adult patients with nonalcoholic fatty liver disease (NAFLD) and healthy control cases.

RESULTS

A total of 51 patients with a mean age of 37.9 ± 9.96 years diagnosed with grade 2-3 hepatosteatosis and 30 healthy control cases with a mean age of 34.8 ± 9.5 years were included in the study. Serum adropin levels in the NAFLD group were statistically significantly lower than in the control cases (588.4 ± 261.0 vs. 894.2 ± 301.2, respectively; p < 0.001). The study participants were further subdivided into 2 groups as patients with (n = 35) or without (n = 46) insulin resistance using the serum homeostatic model of assessment-insulin resistance (HOMA-IR). Serum adropin levels were statistically significantly lower in patients with insulin resistance (p < 0.01). There was a negative correlation between adropin levels and serum insulin, HOMA-IR, urea, gamma-glutamyl transferase, total cholesterol, and triglyceride levels.

CONCLUSION

We observed a decrease in serum adropin levels among adult patients with NAFLD. We also found lower levels of serum adropin in patients with insulin resistance, supporting previous data in the literature. Studies investigating the association of adropin levels with other inflammatory parameters are warranted to define its exact role in the pathogenesis of hepatosteatosis.

ENHO, RXRA, and LXRA polymorphisms and dyslipidaemia, related comorbidities and survival in haemodialysis patients

BACKGROUND

The energy homeostasis-associated gene (ENHO), retinoid X receptor alpha gene (RXRA), and liver X receptor alpha gene (LXRA) are involved in adipogenic/lipogenic regulation. We investigated whether single-nucleotide polymorphisms in these genes (ENHO rs2281997, rs72735260; RXRA rs749759, rs10776909, rs10881578; LXRA rs2279238, rs7120118, rs11039155) are associated with dyslipidaemia, related comorbidities and survival of haemodialysis (HD) patients also tested for T-helper (Th) cell interleukin genes (IL).

METHODS

The study was carried out in 873 HD patients. Dyslipidaemia was diagnosed by the recommendations of the Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines (2003); atherogenic dyslipidaemia was referred to if the TG/HDL cholesterol ratio was equal to or higher than 3.8. Genotyping of ENHO SNPs, LXRA SNPs, and IL12A rs568408 was carried out using HRM analysis. RXRA SNPs, IL12B rs3212227, and IL18 rs360719 were genotyped using PCR-RFLP analysis. The circulating adropin concentration was determined in 126 patients by enzyme-linked immunosorbent assay. Survival probability was analysed using the Kaplan-Meier method in 440 patients followed through 7.5 years.

RESULTS

Dyslipidaemia by K/DOQI was diagnosed in 459 patients (91% revealed hyper-LDL- cholesterolaemia), atherogenic dyslipidaemia was diagnosed in 454 patients, and 231 patients were free of dyslipidaemia by both criteria. The variant allele (T) of ENHO rs2281997 was associated with the hyper-LDL cholesterolaemic pattern of dyslipidaemia by K/DOQI. The frequency of atherogenic dyslipidaemia was lower in T-allele bearers than in CC-genotype patients. The rs2281997 T allele was associated with lower cardiovascular mortality in HD patients showing atherogenic dyslipidaemia. ENHO, RXRA, and LXRA showed epistatic interactions in dyslipidaemia. Circulating adropin was lower in atherogenic dyslipidaemia than in non-atherogenic conditions. RXRA rs10776909 was associated with myocardial infarction. Bearers of LXRA rs2279238, rs7120118 or rs11039155 minor alleles showed higher mortality. ENHO SNP positions fell within the same DNase 1 hypersensitivity site expressed in the Th1 cell line. Epistatic interactions occurred between rs2281997 and Th1 IL SNPs (rs360719, rs568408).

CONCLUSIONS

Atherogenic dyslipidaemia occurs in HD patients in whom ENHO encodes less adropin. ENHO, RXRA, and LXRA SNPs, separately or jointly, are associated with dyslipidaemia, myocardial infarction, and survival in HD patients. Differences in the availability of transcription binding sites may contribute to these associations.

Adropin Is a Key Mediator of Hypoxia Induced Anti-Dipsogenic Effects via TRPV4-CamKK-AMPK Signaling in the Circumventricular Organs of Rats

Water intake reduction (anti-dipsogenic effects) under hypoxia has been well established, but the underlying reason remains unknown. Our previous report indicated that activated TRPV4 neurons in SFO are associated with anti-dipsogenic effects under hypoxia. Although low partial pressure of blood oxygen directly activates TRPV4, humoral factors could also be involved. In the present study, we hypothesize that adropin, a new endogenous peptide hormone, was rapidly increased (serum and brain) concomitant with reduced water intake in early hypoxia. Also, the nuclear expression of c-Fos, a marker for neuronal activation, related to water-consumption (SFO and MnPO) was inhibited. These effects were mitigated by a scavenger, rat adropin neutralizing antibody, which effectively neutralized adropin under hypoxia. Interestingly, injection of recombinant adropin in the third ventricle of the rats also triggered anti-dipsogenic effects and reduced c-Fos positive cells in SFO, but these effects were absent when TRPV4 was knocked down by shRNA. Moreover, adropin-activated CamKK-AMPK signaling related to TRPV4 calcium channel in SFO in normoxia. These results revealed that dissociative adropin was elevated in acute hypoxia, which was responsible for anti-dipsogenic effects by altering TRPV4-CamKK-AMPK signaling in SFO.